authsyschangepwd.c

   1 /*
   2 ** Copyright 2001-2006 Double Precision, Inc.  See COPYING for
   3 ** distribution information.
   4 */
   5
   6 #if     HAVE_CONFIG_H
   7 #include        "courier_auth_config.h"
   8 #endif
   9 #include        <stdio.h>
  10 #include        <stdlib.h>
  11 #include        <string.h>
  12 #include        <signal.h>
  13 #include        <errno.h>
  14 #if     HAVE_UNISTD_H
  15 #include        <unistd.h>
  16 #endif
  17 #include        <pwd.h>
  18 #include        <sys/types.h>
  19 #include        <fcntl.h>
  20 #include        "auth.h"
  21 #include        "authwait.h"
  22 #include        "authchangepwdir.h"
  23 #include        "numlib/numlib.h"
  24
  25 static const char rcsid[]="$Id: authsyschangepwd.c,v 1.10 2006/06/01 10:47:33 mrsam Exp $";
  26
  27 static int dochangepwd(struct passwd *, const char *, const char *);
  28
  29 int auth_syspasswd(const char *service, /* Ignored */
  30                    const char *userid,  /* Generally ignored */
  31                    const char *oldpwd,  /* Old password */
  32                    const char *newpwd)  /* New password */
  33 {
  34         char *cpy=strdup(userid);
  35         struct passwd *pwd;
  36         int rc;
  37
  38         if (!cpy)
  39         {
  40                 perror("malloc");
  41                 errno=EPERM;
  42                 return (-1);
  43         }
  44
  45         if (strchr(cpy, '@'))
  46         {
  47                 free(cpy);
  48                 errno=EINVAL;
  49                 return (-1);
  50         }
  51
  52         pwd=getpwnam(cpy);
  53
  54         if (!pwd)
  55         {
  56                 free(cpy);
  57                 errno=EINVAL;
  58                 return (-1);
  59         }
  60
  61         rc=dochangepwd(pwd, oldpwd, newpwd);
  62
  63         free(cpy);
  64         if (rc == 0)
  65                 return rc;
  66
  67         return (1);  /* Fatal error */
  68 }
  69
  70 #define EXPECT AUTHCHANGEPWDIR "/authsystem.passwd"
  71
  72 static int dochangepwd(struct passwd *pwd,
  73                        const char *oldpwd, const char *newpwd)
  74 {
  75         pid_t p, p2;
  76         int pipefd[2];
  77         int waitstat;
  78         FILE *fp;
  79
  80         signal(SIGCHLD, SIG_DFL);
  81         signal(SIGTERM, SIG_DFL);
  82
  83         if (pipe(pipefd) < 0)
  84         {
  85                 perror("CRIT: authsyschangepwd: pipe() failed");
  86                 errno=EPERM;
  87                 return (-1);
  88         }
  89
  90         p=fork();
  91
  92         if (p < 0)
  93         {
  94                 close(pipefd[0]);
  95                 close(pipefd[1]);
  96                 perror("CRIT: authsyschangepwd: fork() failed");
  97                 errno=EPERM;
  98                 return (-1);
  99         }
 100
 101         if (p == 0)
 102         {
 103                 char *argv[2];
 104
 105                 dup2(pipefd[0], 0);
 106                 close(pipefd[0]);
 107                 close(pipefd[1]);
 108
 109                 close(1);
 110                 open("/dev/null", O_WRONLY);
 111                 dup2(1, 2);
 112
 113                 if (pwd->pw_uid != getuid())
 114                 {
 115 #if HAVE_SETLOGIN
 116 #if HAVE_SETSID
 117                         if (setsid() < 0)
 118                         {
 119                                 perror("setsid");
 120                                 exit(1);
 121                         }
 122 #endif
 123
 124                         setlogin(pwd->pw_name);
 125 #endif
 126                         libmail_changeuidgid(pwd->pw_uid, pwd->pw_gid);
 127                 }
 128
 129                 argv[0]=EXPECT;
 130                 argv[1]=0;
 131
 132                 execv(argv[0], argv);
 133                 perror("exec");
 134                 exit(1);
 135         }
 136
 137         close(pipefd[0]);
 138         signal(SIGPIPE, SIG_IGN);
 139
 140         if ((fp=fdopen(pipefd[1], "w")) == NULL)
 141         {
 142                 perror("CRIT: authsyschangepwd: fdopen() failed");
 143                 kill(p, SIGTERM);
 144         }
 145         else
 146         {
 147                 fprintf(fp, "%s\n%s\n", oldpwd, newpwd);
 148                 fclose(fp);
 149         }
 150         close(pipefd[1]);
 151
 152         while ((p2=wait(&waitstat)) != p)
 153         {
 154                 if (p2 < 0 && errno == ECHILD)
 155                 {
 156                         perror("CRIT: authsyschangepwd: wait() failed");
 157                         errno=EPERM;
 158                         return (-1);
 159                 }
 160         }
 161
 162         if (WIFEXITED(waitstat) && WEXITSTATUS(waitstat) == 0)
 163                 return (0);
 164         errno=EPERM;
 165         return (-1);
 166 }